Me. Stat. tit. 14 § 6957
When a person makes entry into lands or tenements of which the tenant in possession, or those under whom he claims, have been in actual possession for 6 years or more, and withholds from such tenant the possession thereof, the tenant may recover of the person so entering, or of his executor or administrator, the increased value of the premises by reason of the buildings and improvements made by the tenant or by those under whom he claims, to be ascertained by the principles hereinbefore provided. These provisions extend to the grantee or assignee of the tenant in dower and of any other life estate. A lien is created on the premises in favor of such claim, to be enforced by an action commenced within 3 years after such entry. It is no bar to such action if the tenant, to avoid cost, yields to the superior title.
14 M.R.S. § 6957